Blank screen

I have a toshiba 8100 laptop with xp pro. I had a problem with it turning on and found that there was a cracked solder where the charger plus in. i fixed that and everything was working great. one week later after not touching it when the power button is pushed there is a blank screen. i hear the HDD spin and when i hold the power button to turn off i hear 1 beep followed by a lot of shorter beeps. also i have tried a test HDD to see what happens and i hear that HDD spin but still a blank screen. any ideas?