I can't answer all your questions b/c I'm not a windows user per se. If your modem/router does have UPnP capability then that's good. Enable it & in firewall setting on LW & that should fix that side of things & I don't believe port Forw. is then necessary. UPnP is new in LW 4.4 & that's as much as I know about it. It should be able to communicate with your device directly then. For games though that'd be different.

I wonder if your issue is different for your pc. Try getting rid of all those older incompletes that are at 0% in both your incomplete folder & downld window. This will help to speed up LW opening & settling down.

Keep in mind all files are going to be queued as soon as you open LW. Give it some time before working with it. Even allow them all try to connect as they will one by one.

Even if you are firewalled there may be some people able to upload from you. But the majority will be blocked out. Of course the ways to check are 1. After LW's been open for more than 30 mins do this test: Bug Report instructions & sample image Is it True/False? If false then there is a firewall there somewhere. 2. Check your statistics: Tools>Stats 3. Library window to far right of shared files will list those that have found your files under 'hits' & those that have successfully or unsuccessfully been able to upload from you further to the right of that.

As for more suggestions, perhaps another member might be able to suggest something.
(Deleting your LW preferences folder sometimes seems to do some magic here; instructions here: Fixes for Limewire)