Laptop trouble please help

I have been having quiet a few issues with my laptop recently, they are as follows

1, it is very slow i am running windows vista home premium with a 2.2ghz CPU and 1 GB ram i have tried every piece of speed up software i can find and yet nothing works i also went into msconfig and turned off all the unnecessary programs running in the background and i even turned of half of the visual features,the HDD ill admit is rather full could this cause this issue? what should i do?

2, when the laptop starts up it goes through its normal startup routine but lately it has been giving me a black screen which takes somewhat 5 minutes to go away what does this mean and how do i fix it

3, once the laptop has started it works reasonably well excluding the speed but sometimes the whole computer will freeze and it will make a loud beep at me so i try the ctrl+alt+Del thing but no response so i push escape etc until it gets to the point where i have to pull the plug cos nothing works what is this and how do i stop it?

4, on rare occasions usually when i open my movies folder i get a message from Mcaffe telling me that a buffer overflow has been blocked i have searched for an answer for this and came up with comodo firewall i tried it for a while but as i mentioned earlier my laptop is way to slow to run something like that in the background, i have also tried all sorts of scans eg malwarebytes asquared adware mcaffee virus scan etc but to no avail.

5, My laptop also makes a whirring noise all the time which started not too long ago it also puts out a little more heat than usual,

so as you can see the issues are almost endless here is a few things i forgot to mention, my laptop is always up to date as i make sure of it, and my system specs are as follows

AMD mobile sempron 2.2GHZ CPU
ATI x1200 GPU
1 GB ddr2 RAm
MSI Motherboard
Vista home premium

Also i have sent my laptop in under warranty for the weird noise but they found nothing and all of the problems continued as you can see the issues have piled up on me and i have no idea what to do any help/advice would be greatly appreciated and if you need any more info just let me know thanks in advance