Could be mostly an old Windows install thing, maybe Kapersky left crap on there or something. This case, however, is one where more RAM would definitely help. Your browser is eating up RAM, the OS is trying to keep files cached, manage pages, and it's running at the edge of what it can handle. Disabling the swap file while being that close to the edge is not a good solution. It may be faster w/ no page file, but the fundamental problem is the lack of memory.
Maybe, but not enough to worry over. It can benefit IO-bound situations like gaming and content creation by 10+%. Getting more RAM is far more important. However, if you upgrade your RAM affordably, you will be running dual-channel.
Your CPU is crap, and it was crap when it was new, as well. But, that mobo can take
just about any Core 2. If purchasing new, the only option worth considering is the E6600 (Wolfdale).
If you can move to a Core 2 Duo (or nearly that) and double your RAM for <$150, my advice would be to back up your data, do the hardware upgrade portion (CPU, RAM, grease if not a new retail CPU), and re-install. The re-install should take care of issues like the long bootup, which can often be practically impossible to pin down the cause of.
Of course, you might be able to find a better deal on a used CPU. So, if your funds are tight, look around for a few days, or ask on FS/FT (note that you'll need heatsink grease for a used CPU). IMO, a $75 E6600 (Wolfdale 3.06Ghz, 1066MHz FSB) is worth buying new. If funds are tight, a used E4xxx wouldn't be bad at all, for instance, especially when it is ridding the world of one more low-clocked Pentium D.
Also, after doing so, don't bother with any defrag programs, don't install anything you don't use, and avoid any printers that install a bunch of resident agents like they are plague-ridden. If you want decent boot times, you want to keep any important program installations and uninstallations to a minimum, and don't install any crap. That is, if you don't use it, don't install it.
HOWEVER, before you go do all that, check the HDD out, anyway. Now, a Pentium D is bad. And, it seems you can use more RAM. So, I think a CPU+RAM upgrade is in order. But, I do agree with others that there may be something wrong with your HDD, or its configuration, as well. It will only cost time to check it out. For instance, if you are running the HDD is IDE mode, it may run slower. You might also need Intel's RST to get NCQ, if running native/RAID (look that up; Google is not being my friend about it ATM). It could just be a crufty install and a slow CPU, but it would suck to replace those and the find the HDD was remapping sectors left and right, or could just perform better.
If it is running native SATA w/ no NCQ, or IDE mode, if you can set it to AHCI, do that prior to re-installing the OS. Windows 7 enables NCQ automatically if AHCI is enabled. If you don't have an AHCI option (likely), native SATA or RAID would be the next best, but that might require extra software (Intel RST). If you have another PC to use while installing, no big deal. Otherwise, go read up to make sure you are prepared, if it is needed at install time (at least 7 can use USB sticks for drivers).
Since we're on this topic, you have never mentioned what your HDDs are, that I can tell. Would you mind giving those? As in, make and model. Also, what, if any peripherals do you use that have their own drivers (such as D: consumer printers/AIOs)?
It could be inconsequential, but it wouldn't hurt to have better information. Boot times in the 3 minute range are just too long, it's not the CPU's fault, you should have enough memory for it, and the page file should have no significant effect on boot times at all. Meanwhile, most 2TB HDDs today should be fast enough for <1min boot times (starting from the POST finishing) with some tweaking, and <1:30 boot times without any effort. Something is just not right, there.
Not bad advice.
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Maybe, but it depends on needs and budget, and the OP is running a hot out-of-order Atom. If the OP has $300+ to put into the computer, maybe an SSD would be worth it as part of the upgrade. A CPU and RAM upgrade with an SSD for the OS along for the ride would be more of an upgrade for his uses than any new computer with an HDD, but I don't know that a Pentium D that could use more RAM would be worth adding an SSD to, if it has to be an exclusive decision.It is equally a CPU/RAM performance problem. A 2.8GHz Pentium D will be only || faster than an Atom for web browsing. Most non-green HDDs today are more than capable of outrunning that. Using a browser other than Firefox or IE, with plenty of RAM, you will hardly ever be limited by HDD access
(IE seems limited all the time, and FF devs keep reinventing the wheel the wrong way, kicking the SQLite can down the road for the next release cycle). With enough RAM for good file caching, Opera and Chrome run great with any kind of storage.
This, regardless of storage, RAM, or CPU. Ad blocking, and selective whitelisting for JS and Flash make the web tolerable.