Sorry for not noticing this topic for so long.
I need to pay more attention.
Well this is odd. It can't be your specifications, they're fine. I'm not sure if it matters but what version of XP are you using? Like Franch said try compatibility mode first. Do you have SP3 installed? I had 1nsane installed for a long time and then installed SP3; 1nsane would run fine, but it then disappeared from me (possibly virus or something). It now won't install or play for me. So [Your problem] may be caused by SP3.
I've only heard of people having problems running it on Vista. You could register at
www.insaneheat.com and check out the forum for some help. Before you post any topics check out the Vista topic (it's easy to see and there should be a link displayed on the front page of the website) and any other such help topics.
I hoped this helped and I hoped I posted in time!