The reason may the DEP ie. a software of Microsoft installed by default may found in control panel->system->advanced-> performance settings-> DEP.
The functionality of that program is that to stop the services which are used by an other application may misuse it. At that the corresponding service will stopped the os DEP.
The possible ways are use the correct application and other there is no way to disable the DEP.
The server service is responsible for file,print and other so server service is stopped you can not map network drives. It does not require restart just goto services and restart the server service to work again.
The same problem is observed and i disabled the dep in boot.ini refer below
This option is only available on 32-bit versions of Windows when running on processors supporting no-execute protection. It enables no-execute protection (also known as Data Execution Protection – DEP), which results in the Memory Manager marking pages containing data as no-execute so that they cannot be executed as code. This can be useful for preventing malicious code from exploiting buffer overflow bugs with unexpected program input in order to execute arbitrary code. No-execute protection is always enabled on 64-bit versions of Windows on processors that support no-execute protection. There are several options you can specify with this switch:
* /NOEXECUTE=OPTIN Enables DEP for core system images and those specified in the DEP configuration dialog.
* /NOEXECUTE=OPTOUT Enables DEP for all images except those specified in the DEP configuration dialog.
* /NOEXECUTE=ALWAYSON Enables DEP on all images.
* /NOEXECUTE=ALWAYSOFF Disables DEP.