Need Some Help DDos attack

Hiya all New to this Forum and i need some help

My setup :
Windows XP Professional Service Pack 1 (build 2600)
GlobeSpan USB ADSL LAN Modem
Network setup :
Ok basically im on a Standard NAT Network With a Cisco 5000Series Router (that i have no access to)
Security :
System Mechanic Pro 5 AV & Firewall + additional AVG 7 Free Edition

Problem is For about a month Now ive been Getting DDos Attacks
Before i installed Xp i had 98se And that just got all Buggered up With Worms and hundereds of differenet Virus's
Ive been running a application called "Active Ports" and heres the list;
System 4 192.168.5.27 138 LISTEN UDP
System 4 192.168.5.27 137 LISTEN UDP
System 4 0.0.0.0 445 LISTEN UDP
System 4 192.168.5.27 139 LISTEN TCP
System 4 0.0.0.0 1030 LISTEN TCP
System 4 0.0.0.0 445 LISTEN TCP
avgemc.exe 200 127.0.0.1 10110 LISTEN TCP C:\PROGRA~1\Grisoft\AVGFRE~1\avgemc.exe
avgemc.exe 200 127.0.0.1 10025 LISTEN TCP C:\PROGRA~1\Grisoft\AVGFRE~1\avgemc.exe
lsass.exe 564 0.0.0.0 500 LISTEN UDP C:\WINDOWS\system32\lsass.exe
svchost.exe 724 0.0.0.0 135 LISTEN UDP C:\WINDOWS\system32\svchost.exe
svchost.exe 724 0.0.0.0 135 LISTEN TCP C:\WINDOWS\system32\svchost.exe
svchost.exe 748 192.168.5.27 123 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 748 0.0.0.0 1026 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 748 0.0.0.0 1025 LISTEN TCP C:\WINDOWS\System32\svchost.exe
svchost.exe 828 0.0.0.0 1795 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 828 0.0.0.0 1426 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 828 0.0.0.0 1070 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 828 0.0.0.0 1032 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 840 192.168.5.27 1900 LISTEN UDP C:\WINDOWS\System32\svchost.exe
svchost.exe 840 0.0.0.0 5000 LISTEN TCP C:\WINDOWS\System32\svchost.exe
Unknown 1152 0.0.0.0 1125 LISTEN TCP
Unknown 1152 0.0.0.0 1110 LISTEN TCP
IEXPLORE.EXE 2128 192.168.5.27 1985 212.199.222.81 80 ESTABLISHED TCP C:\Program Files\Internet Explorer\IEXPLORE.EXE
IEXPLORE.EXE 2128 127.0.0.1 1842 LISTEN UDP C:\Program Files\Internet Explorer\IEXPLORE.EXE
IEXPLORE.EXE 2128 192.168.5.27 1987 212.199.222.81 80 ESTABLISHED TCP C:\Program Files\Internet Explorer\IEXPLORE.EXE
IEXPLORE.EXE 2128 192.168.5.27 1953 212.199.79.170 80 ESTABLISHED TCP C:\Program Files\Internet Explorer\IEXPLORE.EXE
IEXPLORE.EXE 2128 192.168.5.27 1952 212.199.79.170 80 ESTABLISHED TCP C:\Program Files\Internet Explorer\IEXPLORE.EXE

Now for the last two weeks ive been coming home from work wanting to play some cs:source and every time i load Steam i get informed by System Mechanic that im getting DDos attacked and it automatically Shuts down my Connection .

I dont know what to do im stuck ive tried every possible thing i consider my self reasonbly good with Computers . but i just cant figure this out.
Being on a nat connection Doesnt that make me Safer ?
Do any of those Ports Look Suspisious to anyone?
HOw can i trace who ever is hacking me ? Cause i really wanna find out .... Really do .
Is it possibale the network admin who i had a fight with is sabotaging my connection , and again how CAN I FIND OUT ?
SOme one Help ?

Thanks in advance

Daniel