Hello and welcome GT77 mate I take you mean the lag of the peek preview after touching it with the cursor and I would suggest first you run these if you haven't already. Plus have you installed any new software that you might be able to relate this issue starting up??
[FONT=Arial, sans-serif]https://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html[/FONT]
[FONT=Arial, sans-serif]https://www.sevenforums.com/tutorials/433-disk-check.html < if necessary include the /f and /r in the command line as per Option2 [/FONT]
[FONT=Arial, sans-serif]Often said that the sfc is best run for three consecutive runs – doesn’t take long but it is your choice.[/FONT]
[FONT=Arial, sans-serif]if no change then try these[/FONT]
[FONT=Arial, sans-serif]http://www.superantispyware.com/ [/FONT]
[FONT=Arial, sans-serif]http://www.malwarebytes.org/products/malwarebytes_free/ [/FONT]
[FONT=Arial, sans-serif]http://www.bleepingcomputer.com/download/adwcleaner/[/FONT]
[FONT=Arial, sans-serif]ADW download from bleeping computer delete any rubbish found with the malware scans[/FONT]
[FONT=Arial, sans-serif]NB If anyone who has Kaspersky as their security they may find it will not like ADW running and to stop the nagging just temporarily disbale the Kaspersky while one runs ADW[/FONT]