How do I boot up wit windows xp home I keep getting isassa.exe error

The issue is probably being caused by the Isassa.exe.
Unfortunately, this virus is NOT detected by any software companies yet, as it's still in it's analyzing stage.

If you would like,
I will gladly analyze the file for you, since it will be a few weeks to months before it's recognized by even the larger companies. Please private message me so I can provide you my submittion email address, since my GMail doesn't allow .exe's to be sent.

I have my own anti-virus that I will add it into. Once I receive your file, Ill work on getting you some removal instructions. Otherwise, I'd suggest the following if you don't wish to help everyone out by letting someone get this viruses' definitions out to the public :)

1) Startup your computer in Safe Mode. Press F8 at the main boot screen.
2) Select: Safe Mode
3) login to your Windows Account.
4) Start > Search > Now search for isassa, then delete any isassa files.
5) Start > Run > Type: regedit > Press OK > Now you need to search for any keys or values that contain isassa, then delete them if they don't appear to be part of your system. I ALWAYS ADVISE MAKIGN A BACKUP OF YOUR REGISTRY JUST In case.
6) Restart your computer normally this time, and see if it works.

Good luck =D