installed software problems

vlc media player-libvlc.dll is missing

google earth-msvcp100.dll and some other software that don't show any error message but don't work properly like picassa,kmplayer etc 

i have tried to download the mention dll files and add it to the installed software's location separately it did'nt work 

First what Operating System (XP, Vista 32 bit, Vista 64 bit, 7 32 bit, 7 64 bit) did you install and model of Dell?

Next did you follow the instructions in my wikies A Clean Install of Windows?

Also are you using any optimisation programs or registry cleaning  programs such as uniblue (anything by uniblue) e.g. speedupmypc or Dell PC TuneUp or similar.

These programs are notorious for ruining Microsoft Windows and giving you such problems. I and many other Windows users recommend staying way clear of them (the free ccleaner and related products by piriform) are the only program in this category that we trust.

I definitely recommend staying clear of anything uniblue and Dell PC Tune Up (despite it being Dell branded).

If you aren't using such programs, what security software are you using? It could be a result of an infection. If you are planning reinstalling again follow my wiki A Clean Install of Windows and carry out Step 7a. This will give you a total clean slate.

Finally it could be signs of a failing hard drive, but you would normally have windows boot up problems in this case also. See here to run the diagnostic tests (with any extended tests).

First I wouldn't advertise on a public forum that you aren't using genuine Windows.

However to the issues you are experiencing, partly it may be due to the non-genuine Windows. However the tune up utilities will cause most of the problems I would imagine.

Please try following my wiki A Clean Install of Windows 7. Follow the additional step 7a with the DBAN as personally I wouldn't trust anything left behind on a non-genuine version of Windows.

For installation media download the Windows 7 Home Premium 64 bit with Service Pack 1 .iso from here and make a bootable USB or DVD as instructed. Use this media and when you are asked to enter a product key, select skip. You should then get a 30 days free trial. For security install Microsoft Security Essentials and Malwarebytes' AntiMalware. DO NOT install any tune up utilities or registry cleaners (except for ccleaner and defraggler). Compare this setup to your systems current performance.

After 30 days you can format the system again and get another 30 day free trial however you should probably just buy a product key.