Help w/ XP Logon issues

The company i worked for recently went out of business.
I have the laptop from the company which is now mine. Long Story.

here’s my problem:

In short i can logon w’ my username/pw but i am not an admin. Also, there is more than one domain that i want to remove. No access to domain.

So, I can’t change anything, install anything.
I’ll assume that there is also a domain admin acct. as well?

Is there anything i can do short of wiping out the drive and re-installing XP? Can i even do that?? I do not have the original disk so I’ll need to buy that.

Any suggestions or help would be greatly appreciated.