Help with dell 1505, really need your help

Hello all,
I took my laptop out this morning used it, and everything was working fine, however when i went to sprint to drop off my phone to be fixed i left in in the car with the windows cracked(It's 94 degree's in madison heights, MI) because i know that heat and computers dont get along. After i left, i tried to start it up, it will post, but will not go to windows. I have had a shitty week and some personal issues going on so i cant really focus on where to start looking for the problem. After the post, it shows the windows screen and then goes black instead of going to the login screen. Thanks in advance. Btw, it a core duo cpu, dell model 1505, and its out of warranty, so i cant get help there.