Help please.... general network question

I am a newbie as far as networks are concerned. Here's what I have

--- desktop running XPsp2 (home)
--- laptop running vista
--- a modem connected to the desktop with a cable, and to the laptop
wirelessly.

I think (hope) I have the thing configured to let users on the laptop use
some folders and a printer on the desktop.

It seems to work OK, but (and here's the "but") my desktop has started to
act oddly

It doesn't seem to want to recognize me as an administrator........... and
so I couldn't alter folders etc. I used the 'secret' administrator account
which let me see the security tabs of the folders and regained control over
them. It took some time...... I wished there was a "I am the Master of
This Domain" button.

I seem to be getting a lot of "this is not a valid shortcut" messages. I
cannot drag any shortcuts made in the start menu onto the desktop (or
anywhere else) but I can send them

I get odd things happening when I boot............. computer keep
re-booting.


I run AVG, Zone Alarm (firewall only), spysweeper, defender and have used
MS's malware remover. Everything seems clean. I ran my 'Reg Booster' which
told me I had 1000 problems in the registry. Two days before I had fixed
any problems in it.

Here's my questions:

1. Is it possible that my network is the cause of all these problems?

2. If the answer is "yes" or "no", Is there a place (site, book, etc) where
I can learn about home networks? Googling hasn't helped, as I'm overwhelmed
by choice.

Although my level of knowledge of networks is zero, I've been using a
computer (not the same one ) for 43 years...... An English Electric KDF9
using the language, 'Algol' was the first.

Thanks for you patience

John