Try getting into Safe Mode (by pressing F8 during the boot process). Your laptop's screen will probably look rather odd (because the video driver won't have loaded )but you should still be able to (for example) open Microsoft Word and see if you can type normally.
If everything seems to be OK in Safe Mode, there's obviously a problem with something running at startup when you try to boot normally (which is hogging all of the your laptop's resources). If you've already got Malwarebytes Anti-Malware on your computer, run it while still in Safe Mode. If you've not got it, download the installation file to a different computer and then transfer it via a USB stick to your laptop and install & run it. (If you use 'Safe Mode with networking' you might be able to download the file directly to your laptop. I've never tried accessing the internet while in Safe Mode, so I'm not sure whether it will work or not). Then also run a full scan with your anti-virus program (again, while still in Safe Mode).
You might like to try booting normally again at that point but if you don't (or it still doesn't work as it should) the next thing to do in Safe Mode is to type 'msconfig' into the 'Run' box (via your Start button) and click on the Startup tab. From there, a great deal of trial and error will be needed. You'll have to disable all but the most essential of the startup processes and see if you can then boot normally. If you can, you'll have to keep adding in processes (and rebooting every time) until you find the one that's causing the problem. Once you've found it you can uninstall (or reinstall) the relevant program.
ALTERNATIVELY:
If the problem occurred suddenly (and recently) then it might be far simpler to boot into Safe Mode and go straight to System Restore (from Start > Programs > Accessories >System Tools) to take your laptop's registry back to a date shortly before the problem first arose.