Windows 7: Windows 7 has become too slow suddenly

i have windows 7 ultimate x64, few days back it suddenly became very slow. it takes about 3 mins to show desktop after logging in. then another 3-4 mins before i can use the machine . then also it works very slowly.
someone help .

Can you do a restore, back a week or so ago ?

noh. is there a way to check what's wrong ?

Start running scans. Have you downloaded and installed anything lately ?

Why can`t you do a restore ?

Sounds like you may have picked up some malware. Download (free version) Malwarebytes' Anti-Malware to your desktop
Malwarebytes Anti-Malware Download
* Double-click mbam-setup.exe and follow the prompts to install the program.Right click to run as Administrator, using Windows 7 or Vista.
* At the end, be sure a checkmark is placed next to Update Malwarebytes' Anti-Malware and Launch Malwarebytes' Anti-Malware, then click Finish.
* If an update is found, it will download and install the latest version.
* Once the program has loaded, select Perform full scan, then click Scan.
* When the scan is complete, click OK, then Show Results to view the results.
* Be sure that everything is checked, and click Remove Selected.
* When completed, a log will open in Notepad. Please save it to a convenient location. Copy and Paste that log into your next reply.

will do the scans thn .
didnt install anything new , just saved a few web pages ,

system restore turned off ,

Do not turn off any features of Windows 7, which is the first perfect OS that requires no tweaking that won't come back to bite you.

In addition to the other excellent suggestions, work through these Troubleshooting Steps for Windows 7
which will help you isolate the problem and learn a lot more about the OS.

ok , i see .
was able to install malwarebytes finally , will get the log in few hour(s) i guess .