Dll problem pc wont work says the application or dll c:windowssystem32lsasrv.dll is not a valid windows image ?? please help its an acer aspire 1640 laptop

The OS(Operating System e.g. XP)might have been damaged. Try repairing it through these steps:
1. you must have a bootable cd depending on you OS let's say if you have an XP cd you must have that.
2. after you secured the cd, insert the boot cd and restart th pc then go to bios setup by pressing the value of the setup.
3. once you opened the setup screen which is usually in blue background, go to the boot priority menu then you'll see 1st,2nd, 3rd etc. boot priority.
4. set cd as first priority and HDD as second.
5. save changes then it will automatically restart.
6. when you see "press any key...." just follow it then you'll be brought to the boot setup wait until it finishes searching for drivers until you see the setup
7. check if the hdd needs a repair or not if it needs to, repair it if not, exit the setup or maybe do a fresh installation.

GOD bless!

Dll file missing reinstall windows or recovery disc