My computer doesnot restart the further the more

HI, if I go restart, my computer goes up to Shutting down screen, then screen blanks but stuck here forever. No response on keyboard no mouse. Only I have to power off/on, then boot normally. Firstly this occurred only sporadically, but the later the more frequent up to now when this becomes almost regular.
Interesting fact that when I go "Shut down", the computer shuts down completely (always).
So this issue only comes with Restart.
On the second side, when the restart succeeds, I always (or in most cases) don't have LAN card detected (as if not physically present), while when I boot from poweroff state the LAN card is detected reliably always (or in most cases). This may be related.
This becomes annoying over the time. Any troubleshooting, diagnostics, tips & tricks?

One of the Forum experts prepared these two troubleshooting tutorials. I'd give them a try:

Troubleshooting Windows 7 Failure to Boot

Troubleshooting Steps for Windows 7

Or, if your computer is factory built, you could eliminate the troubleshooting and just go for a clean reinstall.

Clean Reinstall - Factory OEM Windows 7

I want to avoid to clean reinstall. Except this my Windows are in so perfect condition so that I even don't have any needs to upgrade. Maybe this is caused by a faulty driver or registry settings. ( I don't observe these hangs when restarting from Ubuntu). I don't know if those tutorials help with this because this is actually problem of shutdown not boot (but give them a look).

Have you tried the Troubleshooting Steps for Windows 7 tutorial, as suggested by marsmimar?

There are some very useful procedures which will check for damaged files, malware and hardware problems.

Hope this helps,

Harry