Windows Vista Dell Studio 1555 Fail Start

So, today I was caching up on the Olympics through the BBC and my laptop turned itself off. It does sometimes anyway through over heating, and has always in the two years I have owned it. Its a Dell Studio 1555, 32 bit Vista Home. Now when I reboot I receive this message:

Windows failed to start. A recent hardware or software change might be the cause. To ficlx the problem:
1. Insert your windows installation disk and restart your computer.
2. Choose your language settings, and then click "Next".
3. Click "Repair your computer".

If you do not have this disc, contact your system administrator other computer manufacturer for assistance.

File: \Windows\system32\drivers\msisadrv.system
Status: 0xc0000098
Info: Windows failed to load because a critical system driver is missing, or corrupt.

This has happened to me before because of updating itunes, which I understand. Could someone please tell me the reason this time? I did not expect Iplayer to cause difficulties. I never received any kids of disks for my laptop and I would appreciate if anyone knew of any was I could save all of my personal files. if it needs to be wiped then if someone could suggest how that'd be awesome!

Welcome

The reason that you are getting the warning is PROBABLY due to the fact that the shut down caused Hard Drive Damage. If it is not too serious we will be able to save your stuff and get you up and running again. If so you should make a hard drive test and an chhkdsk. We will show you how. First get your stuff. If the hard drive damage is bad you will not be able to load this:
Use Ubuntu Live CD to Backup Files from Your Dead Windows Computer - How-To Geek

So, at the mo I'm logging onto the internet using Ubuntu, and have so far managed to save all of my stuff and get my hands on a Vista disk. I tried booting from the disk, which worked. But the 'Repair' option did nothing, and I do not have a 'Format my Computer' option. Deciding to just reinstall Vista and make things easier for myself, I fell short again as it declined my product key, which is genuine and took some finding until I looked under the battery. Even though I was able to bypass this, it could not install first because of the lack of drivers and then secondly aborted the operation after having begun it. So, is there something else I can try, or have I gone wrong somewhere? Thanks!

This is what you do
Change the boot order to CD
http://www.vistax64.com/tutorials/205005-boot-priority-change.html
Then boot from the CD and follow the online instructions.
When asked for your product key number, just ignore
You can set the computer to give you an extra 90 days if needed.
Lets just try to get it working.

BE SURE, your CD is exactly the same version as it was when you bought the computer.

Sometimes when a computer is abnormally shut down, it's in the process of writing information to the hard drive, and in a split second the writing manages to intrude on system files. This can happen when the shut down has caused various control protocols to be aborted just as power is being lost. However, there's a good chance you could have been able to repair your installation without a full reinstall. But that point is now moot, since you began a Vista installation from scratch.

One other thing: if you're going to continue with this computer, I would do something about the overheating. You should definitely clean out the CPU box, as there may be dust inside, a thick dust layer on the fan blades that slows it down, and even blockages. Make sure the vents in front and back are not blocked by anything. Also, with very old computers, the fan motors can wear down. You might be better off with a newer fan that'll deliver better air flow inside.