Hello.
Oh you messed at server's config, that's why it does not work.
ifconfig 10.10.10.1 255.255.255.255
You don't need this, because you declare this with:
server 10.10.10.0 255.255.255.0
Server's local tunnel adapter always will get 10.10.10.1.
push "route 10.0.0.0 255.0.0.0"
This is your server's LAN mask? If so, then you have to use different IP pool when declaring "server" something like 192.168.10.0 255.255.255.0.
push "dhcp-option DNS 192.168.1.xyz"
Don't hide last decimal in this private IP - it's not a hacking hint. Which lan does bellong that dns?
push "route 0.0.0.0 0.0.0.0"
This is your WinXP problem, because on Win7 route adding at client side seems to be treacky and not always working. Remove this line.