Ok.

For Vista/7 the command to restore the MBR from the recovery console is

Well i fixed the MBR thingy, and my Windows 7 is faster now, but it's still super slow

I would suspect something wrong with the Win/7 install. Run a virus scan.

I have windows 7 installed alongside with Slackware. Lilo is my boot loader and I have zero problems with windows 7 performance. I suspect the problem is with windows 7.

Ok, virusscan should fix and it got better after few mins, maybe just needed warming up....

Windows keeps quite a bit of information about loading programs, and resizing the NTFS partition can make Windows slow for a while. Also, you could have problems with file fragmentation after resizing the Windows partition.

There are a few things you can do to make sure that the NTFS Windows partition is OK and not fragmented.

First, check the file-system for errors.

Click the start button (it looks like a multicolored flag in a circle). Click "All Programs" in the menu. Click the "Accessories" folder. Click the right-hand mouse button on "Command Prompt" in the menu. Click the left-hand mouse button on "Run as administrator". Confirm that you want to run the program as an Administrator if Windows asks you.

You should now have a Windows command prompt window where you can type in commands. Type in this command to request a disk check on drive C:

chkdsk c: /f /x

You will be asked if you want to run the disk check next time Windows restarts. Answer yes by pressing the Y key and the Enter key. Restart the computer and Windows will run the disk check on drive C:

If you want to see the results of the disk check you can watch it while it runs or look in the Windows "Application" Event log. The results have the source "Wininit" and event ID 1001 in the Application event log.

You can de-fragment the disk using the program located in the "Accessories" menu under "System Tools". Click on "Disk Defragmenter".

There are two features that speed up Windows, called the prefetcher and superfetch. Those should not have been disabled by installing Slackware, but it is possible that the information may have become incorrect after resizing the Windows partition. You can find articles on-line that explain how to delete the Windows prefetch information. The prefetch information will be rebuilt after you delete it. There are also registry settings and system services in Windows required for prefetching to work properly. None of those should have been affected by installing Slackware.

Installing LILO has no effect on Windows booting. LILO just loads the same boot block from the Windows partition that would have been loaded by the default Master Boot Record software. The Windows partition's boot block loads a hidden program called "bootmgr" that actually boots Windows. The majority of Windows booting is done by "WINLOAD.EXE" located in the SYSTEM32 folder. All of that works exactly the same after installing LILO.

Windows can be slow for other reasons, so you may also want to use System Restore to restore Windows to an earlier point in time. Back up your most important files before you do that just in case you run into a problem.

Ok, I will run those fixes as soon as I get the chance. Thanks for your help, everyone!
:D

Yep same for me, no probs at all.

Did you check, if W7 kept it's drive letters and how much it uses from RAM and CPU ?

That really sounds like a corrupted ntfs file system or a virus eating up W7's resources