"A lot of partitions", that's strange. Probably you mean something else.

All you can do yourself, I'm afraid is a repair install from your Windows XP CD. http://michaelstevenstech.com/XPrepairinstall.htm tells how to do it. I don't know if consider that an easy fix to do yourself.

When bringing your PC to the tech, just install your business programs on your laptop and restore your business data there from your latest backup so you can continue with your business while he repairs it or until your new PC is ready for use.