Hi - Can I connect a softphone on my PC to the 2820Vn which has a PSTN line connected? (using fxo?)

No; the Vigor2820Vn doesn't have an fXO port.

the specs say it does...

"VoIP Features ('V' Models only):
Two 'FXS' Phone Ports
One 'FXO' Line Port for connection to analogue (POTS) line
Automatic phone switch-over for incoming calls on either PSTN or VoIP
Hotline (Dial preset number when handset lifted)
Digit-Map facility for LCR selection
Protocols: SIP, RTP / RTCP
12 SIP Registrar Accounts (for up to 12 VoIP providers/Trunks)
G.168 Line Echo-cancellation
Automatic Gain Control
Jitter Buffer ( 125ms )
Voice Codecs:
G.711 A / µ Law
G.723.1
G.726
G.729 A / B
"

Well, it doesn't. Where are you getting that info from and did you see that before your first posting?

http://www.draytek.co.uk/products/vigor2820.html

Voice-over-IP

not to mention the physical box I have that matches the photos on the website. I even has my phoneline plugged into it?

It says FXO on the site? whats going on?

And yes I did see that before my first post, I saw that before I bought the device.

This picture is from the Draytek site and clearly shows "FXO"