Facing problem with Windows security

I have a Vaio VGN-Z4GBD which I bought with preinstalled Vista 64 and later I converted to windows 7 opting for the special offer for upgrade. Initially I had lots of trouble but it got settled after some time.
I had auto update on for windows update and after one such update few months back I have started getting a funny problem. If I try to open an adobe acrobat document from my own local drive, the document will open but I will get a false message from windows security saying ’These files can’t be open. Your internet security setting has prevented from one or more files from being opened.’ This was irritating but sooner I found out that many programs I am not able to run because of this kind of file opening error. The internet setting changes have no effect. For the same reason perhaps many programs and utilities are not working when they try to open a file and get any error. Even the Action centre trouble shooting utility is not able to go past this. Any solution other than reinstalling the OS from scratch will be really welcome as I have lots of softwares installed in the PC with their updates.
Cheers

First lets rule out any and all malware, run malwarebytes, adaware and spybot s&d. Then run your antivirus, run full scans not quick scan. Then run Ccleaner to clean out any junk files. Then defrag your hdd.

You will continue to have problems and such, maybe more, since you did an "upgrade" install of Windows 7. A LOT of users have nothing but problems when they "upgraded" from Vista to Windows 7.

The best, surest alternative is to do a clean or custom install of Windows 7 on your system. Many users have used the upgrade disc and have had no issues at all doing it that way.

Believe me, you'll find your system is faster and more responsive than ever before.

Alternate Solution for same error message.
Background

Microsoft Downloads - in my case those from the Microsoft Update Catalog,

but it has also been reported those from Web Update,

Microsoft Downloads Create file / path names in Windows 7 64 bit greater than the maximum allowed within Windows 7 64bit. Note you cannot create over length path names manually in Windows 7.

The maximum is 260 characters including 3 character drive designation plus 1 character <null> terminating character.

The maximum is 256 not counting the drive designator ( i.e. C:\ ) and also not including the <null> terminating character at the end. So the entire directory path plus the file name should be less than or equal to 256 characters. Excluding the three ( 3) character drive designator "C:\" from the 256.

In my case the path downloaded from Microsoft by Microsoft software was greater than 270 bytes in several cases.

The result was the same error.
These files can't be opened.


Your Internet Security settings prevented one or more files from being opened.


Either of the following solutions worked:


Copy the file to a much shorter directory.


or


Rename the file in place so that the entire path, including the file name, is less than 256 characters.


Obviously in these cases the error message is misleading.


It appears this may be a default error message that pops up when the real error is not identified.