User Agent

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; Sleipnir/2.8.5)

This user agent belongs to Sleipnir. Fenrir Inc developed this Browser. This Browser run on WinXP and it renders web contents with Trident on Windows Desktop.

Browser - Sleipnir

Sleipnir

Version2.8 @ 32 bit
DeveloperFenrir Inc
ParentSleipnir 2.8
Platform windows 5.1 (32 bit) by Microsoft Corporation
Device TypeDesktop

Act as 

Mobile No
Tablet No
Crawler No
Fake No
Anonymized No

Capabilities

Rendering EngineTrident by Microsoft Corporation (For Internet Explorer since version 4.0 and embedded WebBrowser controls (such as Internet Explorer shells, Maxthon and some media players).)
Pointingmouse
Javascript Yes
CSS Yes Version: 2
Cookies Yes
Tables Yes
Frames Yes
IFrames Yes
Background Sounds Yes
Java Applets Yes
VB Script Yes
Activex Yes