If I were you, I would reformat the hard drive, install Windows XP, apply the service packs, install any Thinkpad-specific drivers (still available at
www.ibm.com), add some cheap third-party memory.
Gets rid of stuff the corporate IT dept put on there, makes you the administrator, lets you use the more user-friendly Win XP, and it is nicer to have a clean install than some 5 year old install.
Whether this is a DIY job depends on (1) how geeky are you? (2) does the 600 have a bootable CD drive? (3) do you have a desktop PC?
If you don't want to do it yourself and don't have a computer geek neighbor, I bet $50 on Craiglist would find you a rent-a-geek.