Dell Inspiron N5030 has a White Screen After Log On

This problem is seriously driving me crazy, I could smash this computer. 

I own a Dell Insprion N5030 laptop. Basically, I've been having this problem for a bit over three weeks now and it doesn't seem to be going away on it's own. The problem is that the laptop turns on, goes through the Dell and Windows 7 startup and it brings me all the way to the blue log in screen. I type in my password and press enter, then I wait maybe 30 seconds for it to sign in then the screen turns completely white and doesn't change even after 30 minutes of waiting.

Sometimes, after the Dell and Windows 7 startup screens, the screen even goes black for about 10 seconds before it takes me to the blue log in screen. 

I searched online for solutions but couldn't find many. At first, doing a power drain (taking out the plug and battery, pressing the power button for 10 seconds) worked and it became normal once I logged on. However, now I have to power drain the laptop more than 5 times just to get it to go on. 

Before, every time I got it to work, when I shut down, it went back to just not working, leading me back to multiple power drains. Even before, when I got it to finally work, I just kept it on sleep (which wastes electricity) and it would work the next day; but now putting it on sleep brings me back to the white screen. I have tried power drains, restoring Windows to previous versions, and doing disk check multiple times. 

It takes me at least an hour to turn on the computer and get it to work properly. When I finally do get it to work, it is totally fine. I'm getting so tired of wasting my time turning it on when it use to just take 30 seconds to turn on. 

I have called Dell Tech Support and they refused to help me unless I payed a fee of 125 or 250 dollars since I am out of warranty. Though, after I explained my situation to the first man I talked to, he said "this is a software problem, I will transfer you to someone who can help you". I'm not sure if he was 100% right, so can you guys tell me?

Please, I am so desperate to get this computer to work properly. I've only had it for about 3 years and I do not want to tell my Dad to get me a new one. 

PS. Once my computer got water damaged so I soaked it in rice for a week, and another time I completely smashed the screen and I replaced the LCD by myself. I'm saying this just in case that those situations have anything to do with the computer acting this way. 

Two other problems that I have are that my touchpad buttons stopped working just months into use. And the power cable, when plugged in says something along the lines of 'Please make sure Dell power cord is plugged in correctly for the best performance' or something like that. I'm not that concerned over these problem compared to the main problem. 

Thanks so much.