Actually, WinXP Pro VLK CD has 9 slightly different files in i386 folder that make it into a "corp" version
A legit WinXP Pro install CD using a corp lic key does nothing
Also the corp key must fall into certain PID ranges for respective XP Pro, XP Pro SP1, and XP Pro SP2 versions.
I dont know how it was in the past, that is how it is today.
The CD volume label tells you what you have:
for example XP SP1a.....
XP Pro SP1a labels
English Windows XP Professional (SP1a) Retail........ X1APFPP_EN
English Windows XP Home (SP1a) Retail... X1AHFPP_EN
English Windows XP Professional (SP1a) Upgrade.... X1APCCP_EN
English Windows XP Home (SP1a) Upgrade............. X1AHCCP_EN
English Windows XP Professional (SP1a) OEM.......... X1APOEM_EN
English Windows XP Home (SP1a) OEM.... X1AHOEM_EN
English Windows XP Professional (SP1a) VLK/Corporate/Volume............... X1APVOL_EN
English Windows XP Home (SP1a) VLK/Corporate/Volume........ X1AHVOL_EN
English Windows XP Professional (SP1a) MSDN........ X1APFPP_EN
XP Pro labels
http://www.tacktech.com/display.cfm?ttid=226
And this is not a general hardware question