Free windows software for linux

Clearlooks-XPSilver is yet another excellent addition for Gnome users. It is actually a theme that aims to replicate Windows XP Silver color scheme, but the final result is a little different.

Wine is an Open Source implementation of the Windows API on top of X and Unix.
Think of Wine as a compatibility layer for running Windows programs. Wine does not require Microsoft Windows, as it is a completely free alternative implementation of the Windows API consisting of 100% non-Microsoft code, however Wine can optionally use native Windows DLLs if they are available. Wine provides both a development toolkit for porting Windows source code to Unix as well as a program loader, allowing many unmodified Windows programs to run on x86-based Unixes, including Linux, FreeBSD, and Solaris.
Main features:
Binary Compatibility
- Loads Windows 9x/NT/2000/XP, Windows 3.x and DOS programs and libraries
- Win32 compatible memory layout, exception handling, threads and processes
- Designed for POSIX compatible operatings systems (eg. Linux and FreeBSD)
- ``bug-for-bug compatibility with Windows
Graphics
- X11-based graphics allows remote display to any X terminal
- X11, TrueType (.ttf/.ttc) and Windows Bitmap (.fon) Fonts
- DirectX support for games (limited Direct3D support)
- Printing via PostScript driver or legacy native Win16 printer drivers
- Enhanced Metafile (EMF) and Windows Metafile (WMF) driver
- Desktop-in-a-box or mixable windows
- Windows MultiMedia (WinMM) layer support with builtin codecs
Allows Windows program to interface with:
- Sound devices via ALSA, OSS, ARTS, JACK, and libaudio etc
- Multi-lingual keyboards and CJK input method support via XIM
- Modems, serial devices
- Networks (TCP/IP and IPX)
- ASPI Scanners
- Windows Tablets via XInput (eg. Wacom)
Wine API
- Designed for source and binary compatibility with Win32 code
- Win32 API test suite to ensure compatibility
- Compilable on a wide range of C compilers
- Permits mixing of Win32 and POSIX code
- Permits mixing of ELF (.so) and PE (.dll/.exe) binaries in one address space
- Win32 compatible header files
- Automatically generated API documentation
- Resource compiler
- Message compiler
- IDL compiler
- extensive Unicode support
- Internationalization -- Wine supports 16 languages
- Built-in debugger and configurable trace messages
- External memory checker support using Valgrind
- Sample programs
Enhancements:
- Direct3D support on top of WGL instead of GLX for better portability.
- Many DirectSound fixes.
- Still more gdiplus functions.
- Many crypt32 improvements.
- Lots of bug fixes.

Personalbackup project is a company-wide solution for backing up all your Windows machines and Samba shares.

Personalbackup uses a web frontend for the users and administrators. No client software is needed at all to pull backups of your critical data.

EiffelVision 2 is a platform independent GUI library.

EiffelVision2 is a nice GUI toolkit abstraction that works on multiple platforms. Based on GTK for Unix and WEL on Windows.

NdisWrapper implements Windows kernel API and NDIS (Network Driver Interface Specification) API within Linux kernel.

A Windows driver for wireless network card is then linked to this implementation so that the driver runs natively, as though it is in Windows, without binary emulation.