Problem installing photoshop 7

Ok,
Originally, it installed and worked fine. Then, about a couple of months ago, it stopped working properly. That is, when I went file, new, it froze. I could open an existing file and that would work fine.

So I tried uninstalling it and reinstalling it, but this didn't help.
On trying again, it wouldn't install. It started, but after it did the bit where it says its starting install wizard, it stopped doing anything.

However, when I ejected the disk at this point, it still asked for me to put the disk back in.
My dad installed it on his computer at the same time as I did, and it is still working fine.

I don't understand what's going wrong - I think it must be something on my computer, maybe?
Can anyone help?

Thanks,
Ara

Try using a virus scan and virus scan, when you uninstall make sure you do a clean uninstall, so remove all of its registry settings and crapola too including left over dirty directories.