Short answer: you can't. Ports below 1024 can be opened only by root. As per comment - well, you can, using CAP_NET_BIND_SERVICE, but that approach, applied to java bin will make any java program to be run with this setting, which is undesirable, if not a security risk.
The long answer: you can redirect connections on port 80 to some other port you can open as normal user.
Run as root:
# iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080
As loopback devices (like localhost) do not use the prerouting rules, if you need to use localhost, etc., add this rule as well (thanks @Francesco):
# iptables -t nat -I OUTPUT -p tcp -d 127.0.0.1 --dport 80 -j REDIRECT --to-ports 8080
NOTE: The above solution is not well suited for multi-user systems, as any user can open port 8080 (or any other high port you decide to use), thus intercepting the traffic. (Credits to CesarB).
EDIT: as per comment question - to delete the above rule:
# iptables -t nat --line-numbers -n -L
This will output something like:
Chain PREROUTING (policy ACCEPT)
num target prot opt source destination
1 REDIRECT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:8080 redir ports 8088
2 REDIRECT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 redir ports 8080
The rule you are interested in is nr. 2, so to delete it:
# iptables -t nat -D PREROUTING 2
I suspect the disk is just offline in the guest. Did you go do Disk Manager in the VM and bring it on line?
I have to say, though, it's not worth bothering with. I'll bet that if you try to measure the performance overhead of putting fixed VHD on your disk and assigning that to the VM, you won't be able to tell the difference. And if you use the VHD, you can migrate the VM more easily. You can back it up. Etc.
Best Answer
Hyper-V does support Linux as a guest OS, but being it a Microsoft platform, it's obviously more focused on Windows compatibility; here is the official list of supported guest OSes:
http://technet.microsoft.com/en-us/library/cc794868(WS.10).aspx
It could be worth noting that VMware ESXi is also free, and it has a much broader guest OS support (apart from being the market leader in virtualization and a generally much more mature product than Hyper-V).
Also, Hyper-V Server is somewhat painful to manage if you don't have System Center Virtual Machine Manager available: it has no GUI (the physical console can only be used for basic administration), the remote Hyper-V MMC only runs on Windows 7, and if you don't have an Active Directory domain around, things can get tricky. ESXi is much more user friendly, as long as you have at least one Windows PC (XP or later) where you can run the vSphere Client.