surfing the web is pretty much an idle reading. 38C is pretty hot for idle. I think a 3000+ with stock everything should be around 30C idle and 36C load.
I dont think your temps are hot enough to actually affect anything, but if you want to feel safer, take off the heatsink, wipe away the stock paste (use a little isopropyl alcohol if it isn't coming off easily) and reapply the heatsink with some Arctic Silver 5. Do the "grain sized dab of AS5" thing in the center of the CPU and press the heatsink straight down onto it. If your temps aren't solved by that, i'd say the ASUS probe is giving you bad readings.